Ceiling structure



De c. 29, 1936. c. F. oAvls CEILING STRUCTURE Filed Feb. 6, 1952 3 Sheets-Sheet l 1936- c. F. DAVI 2,065,796

CEILING STRUCTURE Filed Feb. 6, 1952 3 Sheets-Sheet 2 1936- c. F. DAVIS 2,065,796

CEILING STRUCTURE Filed Feb. 6, 1952 AQJJJJJ M? m Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE CEILING STRUCTURE ware Application February 6, 1932, Serial No. 591,267

27 Claims.

The present invention relates to a precast slab and to a building construction embodying the same.

In present day building constructions, it is customary to erect a ceiling comprising individual precast slabs suspended from the floor beams and subsequently to lay a floor above the same, the floor either to consist of precast slabs or a pouredin-place construction.

This construction is open to the objection that the ceiling cannot be laid after the floor is in place, with the result that in laying the floor it frequently becomes necessary for the workmen to stand upon the erected ceiling. This necessitates the use of a ceiling having the requisite strength to support the workmen. It is one of the objects of this invention to avoid this necessity and to provide a ceiling construction which may be accurately hung after the floor is in place, and which, hence, will avoid the necessity for workmen standing thereon. As a result, a ceiling construction may be designed considerably lighter than heretofore, with consequent saving in initial cost and cost of erection.

In suspended ceilings of the expanded metal lath type, it is common practice to suspend from the floor girders or the floor itself furring strips to which the metal lath is secured. Plaster is then applied to this lath to produce the ceiling proper. This procedure is open to the objection that it is difficult, if not impossible, to secure an accurately horizontal ceiling, the applied plaster is not of uniform thickness, sufiicient plaster cannot be applied to make a fireproof construction, and when the plaster is applied, time must be allowed for the same to thoroughly set and dry out, which necessarily delays the construction of the building.

It is, therefore, another important object of the invention to provide a ceiling construction which will be of uniform thickness, which may be erected quickly and accurately, which will be of sufficient thickness to constitute a fireproof construction, and which involving as it does the use of precast slabs avoids the necessity of waiting for the same to dry out when in place. Such a construction insures the production of a perfectly horizontal ceiling not heretofore possible with the metal lath type of construction.

Still another object of the invention is the provision of a suspended ceiling of the precast slab type, which will be rigid in both vertical directions, that is, which will not permit of one slab lifting from or out of alignment with a neighboring slab during or subsequent to erection.

Still another important object is the provision of a slab type of ceiling which may be erected regardless of beam or supporting element spacing, that is, any distance between supporting element centers may be used up to the entire length of a unit slab. This means that with this construction, it is not necessary to specially design a steel framework to take such ceilings as has been necessary heretofore, but on the contrary, ceilings according to this invention may be installed in any type of building framework where the supporting element spacing does not exceed the length of a slab. Where buildings are designed with this installation in mind, material savings in steel may be counted on as such spacings may exceed those now thought to be necessary. With this present construction, a ratio of beam spacing to slab thickness of 1811 or greater may be used, not thought possible heretofore.

In carrying out the invention in one of its forms, I provide a precast slab of rectangular form of such dimensions as to insure the rapid erection of large areas of ceiling, the individual slabs, however, being capable of being handled readily by two men. Such a slab by way of example may be made in sizes substantially 15 inches wide, 12 feet long and from 1 inches to 2 inches thick.

In the preferred form of the invention, these individual slabs are edged with metal which serves not only in protecting the thus covered edges, which is desirable if the slabs are made from gypsum or the like, but adds actual strength to the slab as a unit. I prefer to provide these meta-l edges of such form and of such strength that they themselves serve as the suspending means for one edge of the slabs and also a mating joint between adjacent slabs on two or four edges of any particular slab. It is desirable that such slabs be of the ship lap type. As a result of this construction these ceiling slabs may be quickly erected by hanging the same directly from the usual furring strips or floor beams and where the slabs are of the ship lap type, each slab is adapted to be supported at one edge on the previously erected slab and on its opposite edge by a hanger engaging the ceiling supporting means. In the preferred form of the invention, a material thickness of gypsum underlies the metal edging and thus protects the hanging means from distortion in case of fire. As above set forth, each slab is interlocked with its neighbor, with the result that each slab contributes materially to the strength and support of its neighbor.

The invention further consists in the novel arrangement, combination and construction of parts more fully hereinafter described and shown in the accompanying drawings.

In the drawings Fig. l is a perspective View of a building construction embodying the present invention.

Fig. 2 is a sectional View along the line 22 of Fig. 4.

Fig. 3 is a perspective view of a slab constructed according to the invention.

Fig. 4 is a plan View of a ceiling.

Fig. 5 is a View along the line 55 of Fig. 4.

Fig. 6 is a sectional view of a modified slab.

Referring with particularity to the embodiment illustrated, the slabs per se consist essentially of a body of plastic material I having projecting lower longitudinal edge portions 2 and projecting upper lateral edge portions 3. Suitably embedded in one edge portion is a metallic element 4 having preferably the expanded portion 5 completely embedded in the body of plastic material I. I The upper portion of the element 4 is bent back upon itself to form a recess or groove 6. Immediately above the grooved portion the member 4 is extended upwardly to form a substantially vertical flange 1 perforated for a purpose to be described more fully hereinafter.

The opposite edge portion of the slab is also provided with a metallic member 8 having an expanded portion 9 embedded in the plastic material and having a projecting tongue l so constructed and arranged that when two slabs are erected adjacent each other as in Fig. 2, the tongue It! of one metallic member will enter and be enclosed within the groove or recess 6 in the other member 4.

Where desirable, this tongued and grooved arrangement may also be provided at the lateral ends or edge portions of the slab, although this is not an essential requirement.

From an inspection of Fig. 2, it is to be noted that in the erected position the slab A is supported at its right hand longitudinal edge by the left hand longitudinal edge of a slab B; This is by reason of the fact that the tongue ID of slab A is enclosed within the groove 6 of slab B and that the lower projecting portion 2 of the slab B underlies the upper projecting edge portion of the slab A. The slab A is supported at its left hand end by means of a hanger I! engaging the upwardly extending projection l and a furring strip l2 or the like.

The modified form of the invention shown in Fig. 6 illustrates the slabs A and B as having no ship lap joint therebetween, but on the contrary,

q abutting each other on an approximately vertical line. This construction may be desirable under some circumstances. In this modification it is to be noted that the metallic edge members t and 8 which are used to protect and interlock the slabs, are so arranged that the interlock between the metallic parts is located entirely above the surface of the slab. This is in contradistinction to the arrangement shown in Fig. 2, in which the interlocking portions are embedded in the slab to such an extent that the upper surface of the slab and the interlock are substantially flush. The hangers l3 connect the flange l with a beam 14 or the like.

As shown in Fig. 6 a tight driving interlock between the tongue Hi and groove 8 may be insured by bending back the extreme end of the tongue as at E which must be forced into the groove.

In this type of construction, it is to be noted that the turned back end on the tongue serves as a reinforcing bead which not only acts to stifien the tongue and prevents undue distortion of the same during handling, but also acting against the more or less spring top portion of parts constituting the groove 8, forces the entire member 8 and slab A downwardly. Where this ccnstruction is used in combination with a ship lap slab, the slabs at their ship lap engagement are forced together in a tight frictional joint. This contributes materially to the rigidity of the whole structure and prevents any relative vertical movement between adjacent slabs, a very desirable feature. While Fig. 6 shows this construction as applied to the metallic member on the shorter Width of a slab, yet obviously the invention contemplates its application to either the end or longitudinal side edge or both.

It is to be noted that in all forms of the invention, the fact that the metallic edge members are embedded to a material extent in the slab body provides a reinforcement for the edge portion of the slab which is a desirable feature as it is wellknown that gypsum is inherently weak. Due to the fact that the slabs are subjected to more or less rough treatment during shipment and erection, it is extremely desirable that the same be reinforced, and this construction provides this desirable feature.

As shown in Fig. 3, the metallic edge member constituting the reinforcement running longitudinally of the slab is the one used to suspend the slab from the ceiling supporting means. This is not entirely essential, for in some instances it may be found desirable to provide the end reiniorcement or metallic edge member witha similar upstanding flange 7. Again, where necessary, the edge members at opposite edges of the slab may be provided with an exposed upstanding portion to which hanger means may be attached for suspending the ceiling. below a'ceiling supporting means. The preferred form, however, is one in which slabs are of the ship lap variety, at least on one pair of edges and each slab rests at one end in a ship lap joint on its neighbor and at its opposite end is suspended by means of a hanger from a ceiling supporting means, the hanger engaging an exposed portion of a slab reinforcement, which in this case is the edge protecting member which serves also as one member of the mated joint between slabs.

In Fig. l, the side vertical wall of a building is shown at l5 and any suitable type of floor construction at H. I beams or the like are indicated at I3, suitably supported by the members I 8 in the usual manner, so that the bottom flange of such beams are accessible, from which the ceiling slabs may be hung.

When working across a rosin, such for instance as that shown in Fig. 1, it will be apparent that in some instances the last row of slabs must be cut longitudinally to fit. This presents no great problem, however, as the gypsum slabs may be readily cut as by a saw. In such circumstances it may be desirable to use the wire hangers IS to suspend the cut edge of the slab from the ceiling supporting element, the opposite or tongued edge of the slab being supported by the mating joint with the neighboring slabs. This construction is also illustrated in larger detail in the sectional View indicated at Fig. 2.

From an inspection of Fig. 4, it will be seen that it is contemplated to provide these slabs in such lengths as will make unnecessary the special spacing of beams or ceiling supporting elements, for if these slabs are made in lengths, for example .weight.

12 "feet, this being more than the normal distance between beams, the slabs may be erected in a hit or miss relation without regard to this beam spacing, it being only necessary to break joints in order to prevent any weakening of the structure.

It will be apparent from the above, and particularly the showing in' Fig. 1' that a ceiling structure has been provided which may be readily and quickly installed after the floor is in place, and that each slab is suspended at one edge by its neighboring slab and at the pposite end by a hanger which engages a ceiling supporting element. This element may, of course, be a hanger actually dropped from the floor above, a beam used to support the floor above, or a furring strip suitably supported from the floor above or the beam, as the case may be. Each slab being of material dimensions, large areas of ceiling may be erected very quickly and with a minimum amount of effort, particularly as the ship lap serves as a guide. It is also to be noted that no grout is necessary, and therefore these ceilings can be erected in any kind of weather as there is nothing to be affected by moisture and no wet plaster to dry out.

It is an important feature of'the invention that due to the fact that the metallic members along the edges of the slabs are embedded at or near the center thereof, there is a substantial body of gypsum beneath these metallic members to protect the same in case of fire.

It is also an important feature of the invention that in the ship lap relationship between slabs, which may exist either at two opposite edges, at all four edges, or on one of the longer edges, to wit, a longitudinal edge, the metallic mating members constribute materially to the support of the weight of the nearest ship-lapped slab. This is shown clearly in Fig. 2. In other words, there is no tendency for that portion of the slab B underlying the slab A to chip off due to an undue amount of weight thereon, by reason of the fact that the metallic edge members are mated together and sustain the major portion of this This mating joint also renders the two slabs vertically immovable in relation to each other, thus insuring permanent alignment.

It is also to be noted that due to this edge reinforcing and mated joint, it is possible to use a much greater ratio of beam or supporting element spacing to slab thickness than has been possible heretofore. In ordinary precast ceilings using slabs of gypsum without any mating joint, it has been the universal practice to keep this ratio under 18:1. With the ceiling of the present invention, however, this ratio may be increased, that is to more than 18:1, the limitation being obviously that the spacing shall not be greater than the length of the slab. As an example, with slabs 1 inches in thickness, supports need not be closer than 24 inches on centers and for a 2 inch slab, 36 inches. This permissible greater spacing is a chief characteristic of the invention. As such, this construction offers considerable advantages over any comparable precast ceiling now or heretofore offered to the trade. This is a very important consideration in this type of construction.

While the invention has been shown and described with particular reference to a specific type of slab and a building construction embodying the same, yet the invention is to be construed broadly and limited only by the scope of the claims.

I claim:

1. A precast slab of set cementitious material having on two opposite edges thereof metallic members, one of said members having an upstanding flange extending substantially the length of the slab, and projecting above the upper surface of the slab and a portion lying substantially flush with the upper surface of the slab.

2. A rectangular slab comprising a body of set cementitious material and metallic members at opposite edges thereof, one pair of members being tongued, the other pair being grooved, one of said members having an upstanding flange projecting above the upper surface of the slab.

3. A rectangular slab comprising a body of set cementitious material and metallic members at opposite edges thereof, one pair of members being tongued, the other pair being grooved, one of said members having an upstanding flange projecting above the upper surface of the slab, and all of the members having a substantial portion projecting into and embedded in the cementitious body at substantially the mid thickness thereof.

4. A rectangular slab comprising a body of set cementitious material and metallic members at two opposite edges thereof, one of said members being tongued and the other being grooved, one of said members having an upstanding flange substantially the length of the slab and projecting free of the body of cementitious material.

5. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab having a metal edge member provided with a portion matingly engaging a portion of the metal edge member of the neighboring slab and being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element the body of each slab being below the ceiling supporting element.

6'. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element, an opposite pair of edges of each slab being interlocked with its neighbor by a mating joint.

'7. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element, each opposite pair of edges of each slab being interlocked with its neighbor by a mating joint.

8. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element, each slab having tongued and grooved metallic members protecting the edges thereof the metal members on adjacent edges of adjacent slabs being matingly engaged.

9. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element, each slab having tongued and grooved metallic members protecting the edges thereof the metal members on adjacent edges of adjacent slabs being matingly engaged, a portion of said members being substantially flush with one face of such slab.

10. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element, each slab having metallic members protecting opposite edges thereof, with a substantial body of cementitious material below the metallic members.

11. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of reinforced ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element by means of a hanger supportingly engaging a slab reinforcement and the ceiling supporting element.

12. A building construction including ceiling supporting elements, a ceiling supported below the same comprising a series of reinforced ship lap precast slabs, each slab being supported at one edge thereof by a neighboring slab and at the opposite edge from a ceiling supporting element by means of a hanger supportingly engaging a slab reinforcement at an exposed portion and the ceiling supporting element, the major portion of the reinforcement being embedded in the slab.

13. A precast slab of set cementitious material having on one edge thereof a metallic member having a flange vertical to a slab face at one end thereof free of cementitious material, an intermediate groove, and the other end embedded in the body of the slab with a material body of cementitious material below the same.

14. A building construction comprising a precast slab of cementitious material having at one edge thereof a metallic member having a groove, and a second precast slab having at one edge thereof a metallic member having an outstanding tongue, said tongue being turned back upon itself at the end portion, said tongue engaging the groove in a mating joint.

15. A building construction comprising a precast slab of cementitious material having at one edge thereof a metallic member having a groove, and a second precast slab having at one edge thereof a metallic member having an outstanding tongue, said tongue being turned back upon itself at the end portion, said tongue engaging the groove in a mating joint, said slabs being ship-lapped at their adjacent edges, said mating joint forcing the ship-lapped edges together in a vertical direction.

16. A building construction comprising a precast slab of cementitious material having at one edge thereof a metallic member having a groove, and a portion embedded in the body of the slab, and a second precast slab having at one edge thereof a metallic member having an outstanding tongue and a portion embedded in the body of the slab, the tongue engaging the groove in a mating joint, there being a substantial body of cementitious material below the embedded portion of each metallic member.

17. A building construction comprising a precast slab of cementitious material having at one edge thereof a metallic member having a groove, and a portion embedded in the body of the slab, and a second precast slab having at one edge thereof a metallic member having an outstanding tongue and a portion embedded in the body of the slab, the tongue engaging the groove in a mating joint, there being a substantial body of cementitious material below the embedded portion of each metallic member, said slabs being ship-lapped at their adjacent edges, the edge of the slab carrying the grooved metallic member underlying and there contacting with the tongued metallic member.

18. A precast slab of set cementitious material having on two opposite edges thereof metallic members, one of said members having at the top thereof an upstanding flange extending substan tially the length of the slab.

19. A precast slab of set cementitious material having on two opposite edges thereof metallic members, one of said members having an upstanding flange extending substantially the length of the slab and containing a series of perforations.

20. A precast slab of set cementitious material having on two opposite edges thereof metallic members, one of said members having an upstanding vertical flange extending substantially the length of the slab and free of the set cementitious material.

21. A building construction including supporting elements, a ceiling supported below the same comprising a series of precast slabs of set cementitious material, each of which is provided with metal members on at least two opposite edges, the metal members on adjacent edges of adjacent slabs matingly engaging each other, with hanger means engaging a metal edge member of each slab and a supporting element, the edge of the slab opposite the hanger means overlapping and resting upon the edge of the adjoining slab, and supported there solely by reason of said overlap and by reason of the mating engagement of the metal members there.

22. A rectangular slab comprising a body of set cementitious material and metallic members at two opposite edges thereof, one of said members being tongued, and the other correspondingly grooved, with a substantial body of cementitious material below each of said metallic members,

in which one of said metal members has a portion free of cementitious material and is perforated to receive a supporting hanger.

23. A rectangular slab comprising a body of set cementitious material, having metal members bonded on at least two opposite edges, one end of each metal member extending into the slab body, with a substantial body of cementitious material on each side of said end, in which one metal member has a tongue and the opposite member a corresponding groove, the former member overlying two plane faces of the slab at right angles to each other. Y

24. A rectangular slab comprising a body of set cementitious material, having metal members bonded on at least two opposite edges, one end of each metal member extending into the slab body, with a substantial body of cementitious material on each side of said end, in which one metal member has a tongue and the opposite member a corresponding groove, the former member overlaying two plane faces of the slab at right angles to each other, the slab edge carrying the groove member extending outwardly beyond the same.

25. A precast slab for ceilings or the like including a body of set cementitious material, metal members at two opposite edges, one member being a receiving element and the other a receivable element, a portion of one edge of the slab projecting outwardly to form a shoulder, and having metal covering at least the horizontal portion of said shoulder.

26. A ceiling construction including overhead supports, hung ceiling slabs below said supports, including two precast slabs with two edges adjacent, one of said slabs having a projecting shoulder at one edge and having metal covering at least the horizontal portion of said shoulder, one of said slabs having a metal hanger engaging element anchored at one edge, a hanger connecting the hanger engaging element of said slab with the overhead support, the other slab being wholly supported by the hung slab, at the edge adjacent thereto.

27. A building construction including supporting elements, a ceiling supported below the same comprising a series of precast slabs of set cementitious material, each of which is provided with tongued and grooved metal members on at least two opposite edges, said metal members being bonded to the set cementitious material by having a portion embedded therein, the metal members on adjacent edges of adjacent slabs matingly engaging each other.

CLARKE F. DAVIS. 

